Credit

Caption

Sputnik 1, Soviet spacecraft. This spacecraft, the first ever to reach Earth orbit, was launched on 4 October 1957 by the Soviet Union. It was a highly polished aluminium alloy sphere, 58 centimetres in diameter, with four long antennas attached to it. It transmitted radio signals back to Earth for a period of 23 days. The following year, Sputnik 1 burned up as it re-entered Earth's atmosphere on 4 January 1958. This is an exhibition model, photographed in Russia in 1972.